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Device for determining depth of anaesthesia

  • US 4,788,982 A
  • Filed: 01/13/1987
  • Issued: 12/06/1988
  • Est. Priority Date: 01/23/1986
  • Status: Expired due to Fees
First Claim
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1. A device for determining the depth of anaesthesia of a patient, comprising:

  • a measuring means for measuring, on a part of the patient'"'"'s body, a periodically varying optical parameter of blood circulating through said part, said optical parameter having a frequency corresponding to the R-R interval of said patient and said optical parameter having an amplitude corresponding to the blood pressure of the patient, said measuring means including means for generating an electric signal which varies in accord with this parameter;

    signal processing circuit means for receiving said signal generated by said measuring means, said circuit means including means for deriving from said signal a first value representative of variation in the length of successive R-R intervals, as well as means for deriving from said signal a second value representative of variation in the amplitude of said electric signal at a given point during each of said successive intervals, said circuit means also including means for obtaining a ratio of said first and second values;

    whereby said ratio is taken as a measurement of the depth to which the patient is anesthetized.

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